package com.bizcreator.core.web;

import com.bizcreator.core.SessionContextImpl;
import com.bizcreator.core.security.User;
import java.io.IOException;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.io.StringWriter;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

/**
 * 
 * @author lgh
 */
public class LoginFilter implements Filter {

    private static final boolean debug = true;
    // The filter configuration object we are associated with. If
    // this value is null, this filter instance is not currently
    // configured.
    private FilterConfig filterConfig = null;

    public LoginFilter() {
    }

    private void doBeforeProcessing(ServletRequest request,
            ServletResponse response) throws IOException, ServletException {
        if (debug) {
            log("LoginFilter:DoBeforeProcessing");
        }

        // Write code here to process the request and/or response before
        // the rest of the filter chain is invoked.

    }

    private void doAfterProcessing(ServletRequest request,
            ServletResponse response) throws IOException, ServletException {
        if (debug) {
            log("LoginFilter:DoAfterProcessing");
        }

    }

    /**
     *
     * @param request
     *            The servlet request we are processing
     * @param response
     *            The servlet response we are creating
     * @param chain
     *            The filter chain we are processing
     *
     * @exception IOException
     *                if an input/output error occurs
     * @exception ServletException
     *                if a servlet error occurs
     */
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {

        if (debug) {
            log("LoginFilter:doFilter()");
        }

        doBeforeProcessing(request, response);

        Throwable problem = null;

        try {
            // 获取该Filter的配置参数
            String encoding = filterConfig.getInitParameter("encoding");
            String loginPage = filterConfig.getInitParameter("loginPage");
            // request.setCharacterEncoding(encoding); //①

            HttpServletRequest req = (HttpServletRequest) request;
            HttpSession session = req.getSession(true);

            SessionContextImpl.session.set(session);

            // 获取客户请求的页面
            String requestPath = req.getServletPath();

            // 如果session范围的user为null，即表明没有登录
            // 且用户请求的既不是登录页面，也不是处理登录的页面
            if (session.getAttribute(User.USER_KEY) == null && !requestPath.endsWith(loginPage)) {
                // forward到登录页面
                request.setAttribute("tip", "您还没有登录");
                request.getRequestDispatcher(loginPage).forward(request,
                        response);
            } else {
                chain.doFilter(request, response);
            }
        } catch (Throwable t) {
            // If an exception is thrown somewhere down the filter chain,
            // we still want to execute our after processing, and then
            // rethrow the problem after that.
            problem = t;
            t.printStackTrace();
        }

        doAfterProcessing(request, response);

        // If there was a problem, we want to rethrow it if it is
        // a known type, otherwise log it.
        if (problem != null) {
            if (problem instanceof ServletException) {
                throw (ServletException) problem;
            }
            if (problem instanceof IOException) {
                throw (IOException) problem;
            }
            sendProcessingError(problem, response);
        }
    }

    /**
     * Return the filter configuration object for this filter.
     */
    public FilterConfig getFilterConfig() {
        return (this.filterConfig);
    }

    /**
     * Set the filter configuration object for this filter.
     *
     * @param filterConfig
     *            The filter configuration object
     */
    public void setFilterConfig(FilterConfig filterConfig) {
        this.filterConfig = filterConfig;
    }

    /**
     * Destroy method for this filter
     */
    public void destroy() {
    }

    /**
     * Init method for this filter
     */
    public void init(FilterConfig filterConfig) {
        this.filterConfig = filterConfig;
        if (filterConfig != null) {
            if (debug) {
                log("LoginFilter:Initializing filter");
            }
        }
    }

    /**
     * Return a String representation of this object.
     */
    @Override
    public String toString() {
        if (filterConfig == null) {
            return ("LoginFilter()");
        }
        StringBuffer sb = new StringBuffer("LoginFilter(");
        sb.append(filterConfig);
        sb.append(")");
        return (sb.toString());
    }

    private void sendProcessingError(Throwable t, ServletResponse response) {
        String stackTrace = getStackTrace(t);

        if (stackTrace != null && !stackTrace.equals("")) {
            try {
                response.setContentType("text/html");
                PrintStream ps = new PrintStream(response.getOutputStream());
                PrintWriter pw = new PrintWriter(ps);
                pw.print("<html>\n<head>\n<title>Error</title>\n</head>\n<body>\n"); // NOI18N

                // PENDING! Localize this for next official release
                pw.print("<h1>The resource did not process correctly</h1>\n<pre>\n");
                pw.print(stackTrace);
                pw.print("</pre></body>\n</html>"); // NOI18N
                pw.close();
                ps.close();
                response.getOutputStream().close();
            } catch (Exception ex) {
            }
        } else {
            try {
                PrintStream ps = new PrintStream(response.getOutputStream());
                t.printStackTrace(ps);
                ps.close();
                response.getOutputStream().close();
            } catch (Exception ex) {
            }
        }
    }

    public static String getStackTrace(Throwable t) {
        String stackTrace = null;
        try {
            StringWriter sw = new StringWriter();
            PrintWriter pw = new PrintWriter(sw);
            t.printStackTrace(pw);
            pw.close();
            sw.close();
            stackTrace = sw.getBuffer().toString();
        } catch (Exception ex) {
        }
        return stackTrace;
    }

    public void log(String msg) {
        filterConfig.getServletContext().log(msg);
    }
}
